Java tutorial
// Copyright 2015 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. package org.chromium.chrome.browser.ntp.snippets; import android.annotation.SuppressLint; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.Drawable; import android.graphics.drawable.TransitionDrawable; import android.media.ThumbnailUtils; import android.os.StrictMode; import android.os.SystemClock; import android.support.v4.text.BidiFormatter; import android.support.v4.view.ViewCompat; import android.text.format.DateUtils; import android.view.ContextMenu; import android.view.Menu; import android.view.MenuItem; import android.view.MenuItem.OnMenuItemClickListener; import android.view.View; import android.view.View.MeasureSpec; import android.widget.ImageView; import android.widget.RelativeLayout; import android.widget.TextView; import org.chromium.base.ApiCompatibilityUtils; import org.chromium.base.Callback; import org.chromium.base.annotations.SuppressFBWarnings; import org.chromium.base.metrics.RecordHistogram; import org.chromium.chrome.R; import org.chromium.chrome.browser.favicon.FaviconHelper.FaviconImageCallback; import org.chromium.chrome.browser.favicon.FaviconHelper.IconAvailabilityCallback; import org.chromium.chrome.browser.ntp.DisplayStyleObserver; import org.chromium.chrome.browser.ntp.NewTabPageUma; import org.chromium.chrome.browser.ntp.NewTabPageView.NewTabPageManager; import org.chromium.chrome.browser.ntp.UiConfig; import org.chromium.chrome.browser.ntp.cards.CardViewHolder; import org.chromium.chrome.browser.ntp.cards.CardsVariationParameters; import org.chromium.chrome.browser.ntp.cards.DisplayStyleObserverAdapter; import org.chromium.chrome.browser.ntp.cards.ImpressionTracker; import org.chromium.chrome.browser.ntp.cards.NewTabPageRecyclerView; import org.chromium.chrome.browser.offlinepages.OfflinePageBridge; import org.chromium.ui.mojom.WindowOpenDisposition; import java.net.URI; import java.net.URISyntaxException; import java.util.concurrent.TimeUnit; /** * A class that represents the view for a single card snippet. */ public class SnippetArticleViewHolder extends CardViewHolder implements ImpressionTracker.Listener { private static final String PUBLISHER_FORMAT_STRING = "%s - %s"; private static final int FADE_IN_ANIMATION_TIME_MS = 300; private static final int[] FAVICON_SERVICE_SUPPORTED_SIZES = { 16, 24, 32, 48, 64 }; private static final String FAVICON_SERVICE_FORMAT = "https://s2.googleusercontent.com/s2/favicons?domain=%s&src=chrome_newtab_mobile&sz=%d&alt=404"; // ContextMenu item ids. These must be unique. private static final int ID_OPEN_IN_NEW_WINDOW = 0; private static final int ID_OPEN_IN_NEW_TAB = 1; private static final int ID_OPEN_IN_INCOGNITO_TAB = 2; private static final int ID_SAVE_FOR_OFFLINE = 3; private static final int ID_REMOVE = 4; private final NewTabPageManager mNewTabPageManager; private final TextView mHeadlineTextView; private final TextView mPublisherTextView; private final TextView mArticleSnippetTextView; private final ImageView mThumbnailView; private FetchImageCallback mImageCallback; private SnippetArticle mArticle; private int mPublisherFaviconSizePx; private final boolean mUseFaviconService; private final UiConfig mUiConfig; @SuppressFBWarnings("URF_UNREAD_FIELD") private ImpressionTracker mImpressionTracker; /** * Listener for when the context menu is created. */ public interface OnCreateContextMenuListener { /** Called when the context menu is created. */ void onCreateContextMenu(); } private static class ContextMenuItemClickListener implements OnMenuItemClickListener { private final SnippetArticle mArticle; private final NewTabPageManager mManager; private final NewTabPageRecyclerView mRecyclerView; public ContextMenuItemClickListener(SnippetArticle article, NewTabPageManager newTabPageManager, NewTabPageRecyclerView newTabPageRecyclerView) { mArticle = article; mManager = newTabPageManager; mRecyclerView = newTabPageRecyclerView; } @Override public boolean onMenuItemClick(MenuItem item) { // If the user clicks a snippet then immediately long presses they will create a context // menu while the snippet's URL loads in the background. This means that when they press // an item on context menu the NTP will not actually be open. We add this check here to // prevent taking any action if the user has already left the NTP. // https://crbug.com/640468. // TODO(peconn): Instead, close the context menu when a snippet is clicked. if (!ViewCompat.isAttachedToWindow(mRecyclerView)) return true; // The UMA is used to compare how the user views the article linked from a snippet. switch (item.getItemId()) { case ID_OPEN_IN_NEW_WINDOW: NewTabPageUma.recordOpenSnippetMethod(NewTabPageUma.OPEN_SNIPPET_METHODS_NEW_WINDOW); mManager.openSnippet(WindowOpenDisposition.NEW_WINDOW, mArticle); return true; case ID_OPEN_IN_NEW_TAB: NewTabPageUma.recordOpenSnippetMethod(NewTabPageUma.OPEN_SNIPPET_METHODS_NEW_TAB); mManager.openSnippet(WindowOpenDisposition.NEW_FOREGROUND_TAB, mArticle); return true; case ID_OPEN_IN_INCOGNITO_TAB: NewTabPageUma.recordOpenSnippetMethod(NewTabPageUma.OPEN_SNIPPET_METHODS_INCOGNITO); mManager.openSnippet(WindowOpenDisposition.OFF_THE_RECORD, mArticle); return true; case ID_SAVE_FOR_OFFLINE: NewTabPageUma.recordOpenSnippetMethod(NewTabPageUma.OPEN_SNIPPET_METHODS_SAVE_FOR_OFFLINE); mManager.openSnippet(WindowOpenDisposition.SAVE_TO_DISK, mArticle); return true; case ID_REMOVE: // UMA is recorded during dismissal. mRecyclerView.dismissItemWithAnimation(mArticle); return true; default: return false; } } } /** * Constructs a SnippetCardItemView item used to display snippets * * @param parent The ViewGroup that is going to contain the newly created view. * @param manager The NTPManager object used to open an article * @param suggestionsSource The source used to retrieve the thumbnails. * @param uiConfig The NTP UI configuration object used to adjust the article UI. */ public SnippetArticleViewHolder(NewTabPageRecyclerView parent, NewTabPageManager manager, UiConfig uiConfig) { super(R.layout.new_tab_page_snippets_card, parent, uiConfig); mNewTabPageManager = manager; mThumbnailView = (ImageView) itemView.findViewById(R.id.article_thumbnail); mHeadlineTextView = (TextView) itemView.findViewById(R.id.article_headline); mPublisherTextView = (TextView) itemView.findViewById(R.id.article_publisher); mArticleSnippetTextView = (TextView) itemView.findViewById(R.id.article_snippet); mImpressionTracker = new ImpressionTracker(itemView, this); mUiConfig = uiConfig; new DisplayStyleObserverAdapter(itemView, uiConfig, new DisplayStyleObserver() { @Override public void onDisplayStyleChanged(@UiConfig.DisplayStyle int newDisplayStyle) { updateLayout(); } }); mUseFaviconService = CardsVariationParameters.isFaviconServiceEnabled(); } @Override public void onImpression() { if (mArticle != null && mArticle.trackImpression()) { mNewTabPageManager.trackSnippetImpression(mArticle); } } @Override public void onCardTapped() { mNewTabPageManager.openSnippet(WindowOpenDisposition.CURRENT_TAB, mArticle); mArticle.trackClick(); } @Override protected void createContextMenu(ContextMenu menu) { RecordHistogram.recordSparseSlowlyHistogram("NewTabPage.Snippets.CardLongPressed", mArticle.mPosition); mArticle.recordAgeAndScore("NewTabPage.Snippets.CardLongPressed"); OnMenuItemClickListener listener = new ContextMenuItemClickListener(mArticle, mNewTabPageManager, getRecyclerView()); // Create a context menu akin to the one shown for MostVisitedItems. if (mNewTabPageManager.isOpenInNewWindowEnabled()) { addContextMenuItem(menu, ID_OPEN_IN_NEW_WINDOW, R.string.contextmenu_open_in_other_window, listener); } addContextMenuItem(menu, ID_OPEN_IN_NEW_TAB, R.string.contextmenu_open_in_new_tab, listener); if (mNewTabPageManager.isOpenInIncognitoEnabled()) { addContextMenuItem(menu, ID_OPEN_IN_INCOGNITO_TAB, R.string.contextmenu_open_in_incognito_tab, listener); } // TODO(peconn): Only show 'Save for Offline' for appropriate snippet types. if (SnippetsConfig.isSaveToOfflineEnabled() && OfflinePageBridge.canSavePage(mArticle.mUrl)) { addContextMenuItem(menu, ID_SAVE_FOR_OFFLINE, R.string.contextmenu_save_link, listener); } addContextMenuItem(menu, ID_REMOVE, R.string.remove, listener); // Disable touch events on the RecyclerView while the context menu is open. This is to // prevent the user long pressing to get the context menu then on the same press scrolling // or swiping to dismiss an item (eg. https://crbug.com/638854, 638555, 636296) final NewTabPageRecyclerView recyclerView = (NewTabPageRecyclerView) itemView.getParent(); recyclerView.setTouchEnabled(false); mNewTabPageManager.addContextMenuCloseCallback(new Callback<Menu>() { @Override public void onResult(Menu result) { recyclerView.setTouchEnabled(true); mNewTabPageManager.removeContextMenuCloseCallback(this); } }); } /** * Convenience method to reduce multi-line function call to single line. */ private static void addContextMenuItem(ContextMenu menu, int id, int resourceId, OnMenuItemClickListener listener) { menu.add(Menu.NONE, id, Menu.NONE, resourceId).setOnMenuItemClickListener(listener); } /** * Updates the layout taking into account screen dimensions and the type of snippet displayed. */ private void updateLayout() { boolean narrow = mUiConfig.getCurrentDisplayStyle() == UiConfig.DISPLAY_STYLE_NARROW; boolean minimal = mArticle.mCardLayout == ContentSuggestionsCardLayout.MINIMAL_CARD; // If the screen is narrow or we are using the minimal layout, hide the article snippet. boolean hideSnippet = narrow || minimal; mArticleSnippetTextView.setVisibility(hideSnippet ? View.GONE : View.VISIBLE); // If we are using minimal layout, hide the thumbnail. boolean hideThumbnail = minimal; mThumbnailView.setVisibility(hideThumbnail ? View.GONE : View.VISIBLE); // If the screen is narrow, increase the number of lines in the header. mHeadlineTextView.setMaxLines(narrow ? 4 : 2); // If the screen is narrow, ensure a minimum number of lines to prevent overlap between the // publisher and the header. mHeadlineTextView.setMinLines((narrow && !hideThumbnail) ? 3 : 1); // If we aren't showing the article snippet, reduce the top margin for publisher text. RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) mPublisherTextView.getLayoutParams(); int topMargin = mPublisherTextView.getResources() .getDimensionPixelSize(hideSnippet ? R.dimen.snippets_publisher_margin_top_without_article_snippet : R.dimen.snippets_publisher_margin_top_with_article_snippet); params.setMargins(params.leftMargin, topMargin, params.rightMargin, params.bottomMargin); mPublisherTextView.setLayoutParams(params); } public void onBindViewHolder(SnippetArticle article) { super.onBindViewHolder(); mArticle = article; updateLayout(); mHeadlineTextView.setText(mArticle.mTitle); // DateUtils.getRelativeTimeSpanString(...) calls through to TimeZone.getDefault(). If this // has never been called before it loads the current time zone from disk. In most likelihood // this will have been called previously and the current time zone will have been cached, // but in some cases (eg instrumentation tests) it will cause a strict mode violation. StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads(); try { long time = SystemClock.elapsedRealtime(); CharSequence relativeTimeSpan = DateUtils.getRelativeTimeSpanString( mArticle.mPublishTimestampMilliseconds, System.currentTimeMillis(), DateUtils.MINUTE_IN_MILLIS); RecordHistogram.recordTimesHistogram("Android.StrictMode.SnippetUIBuildTime", SystemClock.elapsedRealtime() - time, TimeUnit.MILLISECONDS); // We format the publisher here so that having a publisher name in an RTL language // doesn't mess up the formatting on an LTR device and vice versa. String publisherAttribution = String.format(PUBLISHER_FORMAT_STRING, BidiFormatter.getInstance().unicodeWrap(mArticle.mPublisher), relativeTimeSpan); mPublisherTextView.setText(publisherAttribution); } finally { StrictMode.setThreadPolicy(oldPolicy); } // The favicon of the publisher should match the textview height. int widthSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); int heightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); mPublisherTextView.measure(widthSpec, heightSpec); mPublisherFaviconSizePx = mPublisherTextView.getMeasuredHeight(); mArticleSnippetTextView.setText(mArticle.mPreviewText); // If there's still a pending thumbnail fetch, cancel it. cancelImageFetch(); // If the article has a thumbnail already, reuse it. Otherwise start a fetch. // mThumbnailView's visibility is modified in updateLayout(). if (mThumbnailView.getVisibility() == View.VISIBLE) { if (mArticle.getThumbnailBitmap() != null) { mThumbnailView.setImageBitmap(mArticle.getThumbnailBitmap()); } else { mThumbnailView.setImageResource(R.drawable.ic_snippet_thumbnail_placeholder); mImageCallback = new FetchImageCallback(this, mArticle); mNewTabPageManager.getSuggestionsSource().fetchSuggestionImage(mArticle, mImageCallback); } } // Set the favicon of the publisher. try { fetchFaviconFromLocalCache(new URI(mArticle.mUrl), true); } catch (URISyntaxException e) { setDefaultFaviconOnView(); } } private static class FetchImageCallback extends Callback<Bitmap> { private SnippetArticleViewHolder mViewHolder; private final SnippetArticle mSnippet; public FetchImageCallback(SnippetArticleViewHolder viewHolder, SnippetArticle snippet) { mViewHolder = viewHolder; mSnippet = snippet; } @Override public void onResult(Bitmap image) { if (mViewHolder == null) return; mViewHolder.fadeThumbnailIn(mSnippet, image); } public void cancel() { // TODO(treib): Pass the "cancel" on to the actual image fetcher. mViewHolder = null; } } private void cancelImageFetch() { if (mImageCallback != null) { mImageCallback.cancel(); mImageCallback = null; } } private void fadeThumbnailIn(SnippetArticle snippet, Bitmap thumbnail) { mImageCallback = null; if (thumbnail == null) return; // Nothing to do, we keep the placeholder. // We need to crop and scale the downloaded bitmap, as the ImageView we set it on won't be // able to do so when using a TransitionDrawable (as opposed to the straight bitmap). // That's a limitation of TransitionDrawable, which doesn't handle layers of varying sizes. Resources res = mThumbnailView.getResources(); int targetSize = res.getDimensionPixelSize(R.dimen.snippets_thumbnail_size); Bitmap scaledThumbnail = ThumbnailUtils.extractThumbnail(thumbnail, targetSize, targetSize, ThumbnailUtils.OPTIONS_RECYCLE_INPUT); // Store the bitmap to skip the download task next time we display this snippet. snippet.setThumbnailBitmap(scaledThumbnail); // Cross-fade between the placeholder and the thumbnail. Drawable[] layers = { mThumbnailView.getDrawable(), new BitmapDrawable(mThumbnailView.getResources(), scaledThumbnail) }; TransitionDrawable transitionDrawable = new TransitionDrawable(layers); mThumbnailView.setImageDrawable(transitionDrawable); transitionDrawable.startTransition(FADE_IN_ANIMATION_TIME_MS); } private void fetchFaviconFromLocalCache(final URI snippetUri, final boolean fallbackToService) { mNewTabPageManager.getLocalFaviconImageForURL(getSnippetDomain(snippetUri), mPublisherFaviconSizePx, new FaviconImageCallback() { @Override public void onFaviconAvailable(Bitmap image, String iconUrl) { if (image == null && fallbackToService) { fetchFaviconFromService(snippetUri); return; } setFaviconOnView(image); } }); } // TODO(crbug.com/635567): Fix this properly. @SuppressLint("DefaultLocale") private void fetchFaviconFromService(final URI snippetUri) { // Show the default favicon immediately. setDefaultFaviconOnView(); if (!mUseFaviconService) return; int sizePx = getFaviconServiceSupportedSize(); if (sizePx == 0) return; // Replace the default icon by another one from the service when it is fetched. mNewTabPageManager.ensureIconIsAvailable(getSnippetDomain(snippetUri), // Store to the cache for the whole domain. String.format(FAVICON_SERVICE_FORMAT, snippetUri.getHost(), sizePx), /*useLargeIcon=*/false, /*isTemporary=*/true, new IconAvailabilityCallback() { @Override public void onIconAvailabilityChecked(boolean newlyAvailable) { if (!newlyAvailable) return; // The download succeeded, the favicon is in the cache; fetch it. fetchFaviconFromLocalCache(snippetUri, /*fallbackToService=*/false); } }); } private int getFaviconServiceSupportedSize() { // Take the smallest size larger than mFaviconSizePx. for (int size : FAVICON_SERVICE_SUPPORTED_SIZES) { if (size > mPublisherFaviconSizePx) return size; } // Or at least the largest available size (unless too small). int largestSize = FAVICON_SERVICE_SUPPORTED_SIZES[FAVICON_SERVICE_SUPPORTED_SIZES.length - 1]; if (mPublisherFaviconSizePx <= largestSize * 1.5) return largestSize; return 0; } private String getSnippetDomain(URI snippetUri) { return String.format("%s://%s", snippetUri.getScheme(), snippetUri.getHost()); } private void setDefaultFaviconOnView() { setFaviconOnView(ApiCompatibilityUtils.getDrawable(mPublisherTextView.getContext().getResources(), R.drawable.default_favicon)); } private void setFaviconOnView(Bitmap image) { setFaviconOnView(new BitmapDrawable(mPublisherTextView.getContext().getResources(), image)); } private void setFaviconOnView(Drawable drawable) { drawable.setBounds(0, 0, mPublisherFaviconSizePx, mPublisherFaviconSizePx); ApiCompatibilityUtils.setCompoundDrawablesRelative(mPublisherTextView, drawable, null, null, null); mPublisherTextView.setVisibility(View.VISIBLE); } @Override public boolean isDismissable() { return !isPeeking(); } }